Germany's initial military strategy at the outbreak of World War I was primarily based on the Schlieffen Plan, which aimed to quickly defeat France before turning to fight Russia. Therefore, the correct option is:
B) To defend France quickly before turning to Russia.
The Schlieffen Plan called for a rapid invasion of France through Belgium, hoping to secure a quick victory over the French forces. Afterward, the German military would redirect its efforts to the eastern front against Russia, which they expected would take longer to mobilize.